Choose a space large enough for the children to comfortably and safely move about. If there are objects in the way, especially fragile or potentially dangerous ones, move them to another area. Have your CD player and camera nearby and easily within reach.
Explain the exercise they will be participating in. Tell them that the goal is for them to dance to music and when you give the proper command, they will need to hold a pose long enough for you to take a picture. Encourage them to be silly and remind them of the many faces and poses they often make in front of mirrors.
Show the kids your chosen selection of music and ask them to pick which songs to dance to. Prepare the music in your CD player and tell them to get ready. Grab your camera so that you are ready as well.
Tell the kids that the command phrase is "strike a pose!" and that they will need to freeze in an interesting or funny position when you announce it. Immediately start the song and let it play for a little while, allowing them to giggle and loosen up. Be on the lookout for an appropriate time for you to shout out the command, and have your camera ready to shoot.
Shout "strike a pose!" and as soon as they are still, snap away with your camera. They should hold it long enough for you to shoot them at different angles. Remind them that they will get to view their poses when you are done with the exercise. This will encourage them to really ham it up.
Continue the game, allowing them to choose the music and get more creative with their posing. When you notice a drain in energy, announce the final pose is coming up and they should strike their best pose yet.
View the pictures together on your computer, sharing comments and laughter.